1. Field of the Invention
The present invention relates in general to a technique for fabricating patterned crystals having two dimensionally periodic surface structures with nanometer-scale spacings.
2. Description of the Background Art
As the demand for smaller and smaller electronic devices, magnetic recording media, etc., has increased, a need has been created for improved fabrication processes for making such devices. Many such devices are or can be typically formed on substrates that have two-dimensional patterns of periodic surface structures that are used for the subsequent formation of the devices. The reduced size demands for the devices require that the spacings between the periodic structures be on the order of less than 100 nm. Unfortunately, previously known techniques for forming nanometer-scale patterns are not commercially feasible. For example, a number of lithographic methods exist that can be used to form these types of patterned structures. These methods include creating patterns in polymers, called resists, using microlithography based on short wavelength UV radiation or electron beams. Patterns can be formed because the solubility of polymers is changed by the imaging radiation, and when exposed to a solvent a portion of the polymer film is removed quickly to create the image. However, producing dimensions on a length-scale of less than 100 nm using these techniques is difficult and can be carried out only using very special imaging tools and materials.
The tremendous success of scanning probe microscopes has opened the way for the development of another fabrication technique known as proximal probe lithography. Very briefly, proximal probe lithography involves the use of a scanning tunneling (STM) or atomic force microscope (AFM). The techniques range from using the STM to define a pattern in a medium which is subsequently replicated in the underlying material, to STM induced materials deposition, and STM and AFM manipulation of nanometer scale structures. However, there is a significant amount of instrumental evolution that needs to take place before these proximal probe techniques can be practical in a high throughput environment. As a result, a need therefore still remains for a technique that can be employed to form nanometer-scale periodic structures and arrays that is simple and commercially practical.